Nitrogen-containing heterocyclic compound

ABSTRACT

A nitrogen-containing heterocyclic compound is represented by Formula (I): wherein R 1  represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; A represents a heterocyclic residue that contains at least one nitrogen atom and forms a six-membered aromatic heterocyclic ring; and n represents an integer of from 1 to 3.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 12/552,619,filed Sep. 2, 2009, and claims priority to Japanese Patent ApplicationNo. 2009-062869, filed on Mar. 16, 2009. The prior applications,including the specifications, drawings and abstracts are incorporatedherein by reference in their entirety.

BACKGROUND

1. Technical Field

The present invention relates to a nitrogen-containing heterocycliccompound.

2. Related Art

If generated charges are efficiently received and quickly transferred inorganic photoreceptors or organic electronic devices such as organicelectroluminescence devices, organic transistors and organic opticalmemories, the lifespan and performance thereof can be improved.Therefore, the role of charge transporting materials has becomeimportant in this regard.

Charge transporting materials are being developed, and attention isbeing focused on improving characteristics such as charge mobility andcharge-injection capability.

Charge transporting materials are required to have various propertiessuch as solubility, film forming ability and heat resistance. Forexample, for organic electrophotographic photoreceptors, chargetransporting materials are required to have high solubility in organicsolvents and low residual potential. For organic electroluminescencedevices, charge transporting materials are required to have brightemission and to maintain high stability over repeated use.

Well known charge transporting materials for electronic devices includecharge transporting polymers typified by polyvinylcarbazole (PVK) andaromatic amine compounds such as N,N-di(m-tolyl)N,N′-diphenylbenzidine,1,1-bis[N,N-di(p-tolyl)aminophenyl]cyclohexane and4-(N,N-diphenyl)aminobenzaldehyde-N,N-diphenylhydrazone compounds.

SUMMARY

According to an aspect of the present invention, there is provided anitrogen-containing heterocyclic compound represented by Formula (I):

In Formula (I), R¹ represents a hydrogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms or a substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms; A representsa heterocyclic residue that contains at least one nitrogen atom andforms a six-membered aromatic heterocyclic ring; and n represents aninteger of from 1 to 3.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 is the infrared absorption spectrum of the compound obtained inExample 1;

FIG. 2 is the NMR spectrum of the compound obtained in Example 1;

FIG. 3 is the infrared absorption spectrum of the compound obtained inExample 2;

FIG. 4 is the NMR spectrum of the compound obtained in Example 2;

FIG. 5 is the infrared absorption spectrum of the compound obtained inExample 3;

FIG. 6 is the NMR spectrum of the compound obtained in Example 3;

FIG. 7 is the infrared absorption spectrum of the compound obtained inExample 4; and

FIG. 8 is the NMR spectrum of the compound obtained in Example 4.

DETAILED DESCRIPTION

In an exemplary embodiment, the nitrogen-containing heterocycliccompound is a compound represented by Formula (I) below.

In Formula (I), R¹ represents a hydrogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms or a substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms; A representsa heterocyclic residue that contains at least one nitrogen atom andforms a six-membered aromatic heterocyclic ring; and n represents aninteger of from 1 to 3.

In Formula (I), the alkyl group represented by R¹ has 1 to 20 carbonatoms. From the viewpoint of solubility in organic solvents, the alkylgroup represented by R¹ preferably has 1 to 12 carbon atoms, and morepreferably 4 to 8 carbon atoms.

The alkyl group represented by R¹ may be any of a straight chain, abranched chain and a cyclic group. From the viewpoint of solubility inorganic solvents, it is preferably a straight-chain alkyl group.

The alkyl group represented by R¹ may have a substituent, examples ofwhich include halogen atoms (such as chlorine, bromine and fluorineatoms) and the like.

While the alkyl group represented by R¹ may have a substituent, it ispreferably an unsubstituted alkyl group from the viewpoint of deliveringhole transporting performance and increasing solubility.

In Formula (I), the alkoxy group represented by R¹ has 1 to 20 carbonatoms. From the viewpoint of solubility in organic solvents, the alkoxygroup represented by R¹ preferably has 1 to 12 carbon atoms, and morepreferably 4 to 8 carbon atoms.

The alkoxy group represented by R¹ may be any of a straight chain, abranched chain and a cyclic group. From the viewpoint of solubility inorganic solvents, it is preferably a straight-chain alkoxy group.

The alkoxy group represented by R¹ may have a substituent, examples ofwhich include halogen atoms (such as chlorine, bromine and fluorineatoms) and the like.

While the alkoxy group represented by R¹ may have a substituent, it ispreferably an unsubstituted alkoxy group from the viewpoint ofsolubility, crystallinity, hole transporting properties, or the like.

Among these, R¹ in Formula (I) is preferably a hydrogen atom or asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms,more preferably a hydrogen atom or an unsubstituted alkyl group having 1to 20 carbon atoms, still more preferably an unsubstituted alkyl grouphaving 1 to 12 carbon atoms, and furthermore preferably an unsubstitutedstraight-chain alkyl group having 4 to 8 carbon atoms.

In Formula (I), the substituent R¹ is preferably in 3- or 4-position ofthe benzene ring, more preferably in 4-position of the benzene ring,relative to the thiophene ring which is in 1-position), from theviewpoint of hole transporting performance.

In Formula (I), n represents an integer of from 1 to 3, and preferably 1or 2.

In Formula (I), A represents a heterocyclic residue that contains atleast one nitrogen atom and forms a six-membered aromatic heterocyclicring. The six-membered aromatic heterocyclic ring formed by the Aresidue is preferably triazine, a triazine derivative, pyrazine, or apyrazine derivative, from the viewpoint of delivering chargetransporting performance.

Therefore, the compound represented by Formula (I) is preferably apyrazine derivative represented by Formula (II) below or a triazinederivative represented by Formula (III) below.

In Formula (H), R¹ represents a hydrogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms or a substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms; and n eachindependently represent an integer of from 1 to 3.

R¹ and n in Formula (II) have the same meaning and preferred range as R¹and n in Formula (I).

The pyrazine derivative represented by Formula (II) has thiophene groupsintroduced in 2- and 6-positions of the pyrazine ring. The pyrazinederivative represented by Formula (II) having such a structure has highsolubility in organic solvents and improved film-forming ability.Particularly when R¹ is an alkyl group having 1 to 12 carbon atoms, ithas higher solubility in organic solvents, and when the alkyl group isunsubstituted, it is particularly suitable as a hole transportingmaterial.

The pyrazine derivative represented by Formula (II) having thiophenegroups introduced in 2- and 6-positions of the pyrazine ring also hasgood molecular orientation, when formed into a thin film.

In Formula (III), R¹ represents a hydrogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms or a substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms; R² representsa hydrogen atom, a substituted or unsubstituted alkyl group having 1 to10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to10 carbon atoms, a substituted or unsubstituted aryl group having 6 to10 carbon atoms, or a substituted or unsubstituted aryloxy group having6 to 10 carbon atoms; and n represents an integer of from 1 to 3.

R¹ and n in Formula (III) have the same meaning and preferred range asR¹ and n in Formula (I).

In Formula (III), the alkyl group represented by R² has 1 to 10 carbonatoms. From the viewpoint of solubility in organic solvents, the alkylgroup represented by R² preferably has 1 to 4 carbon atoms.

The alkyl group represented by R² may be any of a straight chain, abranched chain and a cyclic group, and it is preferably a straight-chainalkyl group from the viewpoint of solubility in organic solvents.

The alkyl group represented by R² may have a substituent, examples ofwhich include halogen atoms (such as chlorine, bromine and fluorineatoms) and the like.

While the alkyl group represented by R² may have a substituent, it ispreferably an unsubstituted alkyl group from the viewpoint of solubilityin organic solvents.

In Formula (III), the alkoxy group represented by R² has 1 to 10 carbonatoms. From the viewpoint of solubility in organic solvents, the alkoxygroup represented by R² preferably has 1 to 4 carbon atoms, and is morepreferably a methoxy group.

While the alkoxy group represented by R² may be any of a straight chain,a branched chain and a cyclic group, it is preferably a straight-chainalkoxy group from the viewpoint of solubility in organic solvents.

The alkoxy group represented by R² may have a substituent, examples ofwhich include halogen atoms (such as chlorine, bromine and fluorineatoms) and the like.

While the alkoxy group represented by R² may have a substituent, it ispreferably an unsubstituted alkoxy group from the viewpoint ofsolubility in organic solvents.

In Formula (III), the aryl group represented by R² has 6 to 10 carbonatoms. From the viewpoint of solubility in organic solvents, the arylgroup represented by R² is more preferably a phenyl group.

The aryl group represented by R² may have a substituent, examples ofwhich include an alkyl group, a halogen atom group and the like. Thesubstituent is preferably an alkyl group having I to 10 carbon atoms.

In Formula (III), the aryloxy group represented by R² has 6 to 10 carbonatoms. From the viewpoint of solubility in organic solvents, the aryloxygroup represented by R² is more preferably a phenoxy group.

The aryloxy group represented by R² may have a substituent, examples ofwhich include an alkyl group, a halogen atom group and the like. Thesubstituent is preferably an alkyl group having 1 to 10 carbon atoms.

Among these, R² in Formula (HI) is preferably a substituted orunsubstituted alkoxy group having 1 to 10 carbon atoms, more preferablyan unsubstituted alkoxy group having 1 to 10 carbon atoms, even morepreferably an unsubstituted alkoxy group having 1 to 4 carbon atoms,still more preferably an unsubstituted straight-chain alkoxy grouphaving 1 to 4 carbon atoms, and furthermore preferably a methoxy group.

The triazine derivative represented by Formula (III) has thiophenegroups in 2- and 6-positions of the triazine ring. The compoundrepresented by Formula (III) has high solubility in organic solvents andis useful for the production of electronic components by coating methodsor the like, compared to compounds having thiophene groups in 2-, 4- and6-positions of the triazine ring.

When R¹ in Formula (III) is an alkyl group having 1 to 12 carbon atoms,the triazine derivative represented by Formula (III) can have highersolubility in organic solvents.

The triazine derivative represented by Formula (III) has a phenylgroup-substituted thiophene ring. Such a structure has excellent holetransporting properties.

The triazine derivative represented by Formula (III) also has excellentmolecular orientation, when formed into a thin film.

The examples of the nitrogen-containing heterocyclic compoundrepresented by Formula (I) are shown below, which include examples ofthe pyrazine derivative represented by Formula (II) shown in Table 1below and examples of the triazine derivative represented by Formula(III) shown in Table 2 below. The examples shown below are not intendedto limit the scope of the invention.

TABLE 1 No R¹ Bond position n II-1 H — 1 II-2 CH₃— 3 1 II-3 CH₃— 4 1II-4 C₂H₅— 3 1 II-5 C₂H₅— 4 1 II-6 CH₃(CH₂)₃— 4 1 II-7 (CH₃)₃C— 4 1 II-8CH₃(CH₂)₅— 4 1 II-9 CH₃(CH₂)₇— 4 1 II-10 CH₃(CH₂)₃— 4 2 II-11 CH₃(CH₂)₇—4 2 II-12 CH₃(CH₂)₁₁— 4 2 II-13 CH₃(CH₂)₃— 4 3 II-14 CH₃(CH₂)₇— 4 3II-15 CH₃O— 3 1 II-16 CH₃O— 4 1 II-17 C₂H₅O— 4 1 II-18 CH₃(CH₂)₃O— 3 2II-19 CH₃(CH₂)₃O— 4 1 II-20 CH₃(CH₂)₇O— 4 3

TABLE 2 Bond No. R¹ position n R² III-1 H — 1 CH₃O— III-2 CH₃— 3 1 CH₃O—III-3 CH₃— 4 1 CH₃O— III-4 C₂H₅— 3 1 CH₃(CH₂)₂O— III-5 C₂H₅— 4 1 CH₃O—III-6 CH₃(CH₂)₃— 4 1 H III-7 CH₃(CH₂)₃— 4 1 CH₃O— III-8 (CH₃)₃C— 4 1CH₃O— III-9 CH₃(CH₂)₅— 4 1 CH₃O— III-10 CH₃(CH₂)₇— 4 1 CH₃O— III-11CH₃(CH₂)₃— 4 2 CH₃O— III-12 CH₃(CH₂)₇— 4 2 CH₃O— III-13 CH₃(CH₂)₁₁— 4 2CH₃O III-14 CH₃(CH₂)₃— 4 3 CH₃O— III-15 CH₃(CH₂)₇— 4 3 CH₃O— III-16CH₃O— 3 1 CH₃O— III-17 CH₃O— 4 1 CH₃O— III-18 C₂H₅O— 4 2 CH₃O— III-19CH₃(CH₂)₃O— 3 1 H III-20 CH₃(CH₂)₃O— 4 1 CH₃— III-21 CH₃(CH₂)₃O— 4 1C₆H₅— III-22 CH₃(CH₂)₃O— 4 2 CH₃O— III-23 CH₃(CH₂)₃O— 3 1 C₆H₅O— III-24CH₃(CH₂)₇O— 4 3 CH₃O—

The nitrogen-containing heterocyclic compound represented by Formula (I)is useful as a charge transporting material and may be typically usedfor organic photoreceptors (electrophotographic photoreceptors) andorganic electronic devices such as organic electroluminescence devices,organic transistors, organic solar cells, or organic memories.

EXAMPLES

The present invention is more specifically described by the examplesbelow, which are not intended to limit the scope of the invention.

Method of Measuring Charge Mobility

In this example, the charge mobility of the object is measured by theTime-of-Flight method (using a TOF-401 manufactured by OptelCorporation, Ltd.; excitation light source: nitrogen pulsed laser(wavelength 337 nm); applied voltage: 30 V/μm). Unless otherwise stated,the charge mobility measurement is performed using a film of adispersion containing 40% by mass of the object in polycarbonate.

Method of Measuring Ionization Potential

The ionization potential of the object is measured in the air using aphotoelectron spectrometer (AC-2 manufactured by RIKEN KEIKI Co., Ltd.).

Method of Evaluating Solubility

The object is added into each of dichloroethane, toluene andchlorobenzene so that the concentration of the object is 2% by mass.After the mixture is stirred, the state of the resulting solution isvisually observed for the evaluation of the solubility. The solventspecies used are generally suitable for use in the preparation ofelectronic devices. The solubility is evaluated according to thecriteria below.

-   A: In the visual inspection, the object is completely dissolved.-   B: In the visual inspection, a small amount of the object is    precipitated.-   C: In the visual inspection, the object is almost insoluble, and a    large amount of the object is precipitated.

Method of Identification

The object is identified by ¹H-NMR spectroscopy (¹H-NMR UNITY-300manufactured by Varian, Inc., 300 MHz, solvent CDCl₃) and IRspectroscopy (by KBr disk method with a Fourier transform infraredspectrophotometer (FT-730 manufactured by HORIBA, Ltd., resolution 4cm“).

Example 1 Synthesis of Compound (II-6)

A solution including 4.0 g (27 mmol) of 2,6-dichloropyrazine(manufactured by Tokyo Chemical Industry Co., Ltd.), 7.5 g (59 mmol) of2-thiopheneboronic acid (manufactured by Tokyo Chemical Industry Co.,Ltd.), and 0.43 g (0.37 mmol) oftetrakis(triphenylphosphine)palladium(0) (hereinafter also referred toas Pd(PPh₃)₄, manufactured by Tokyo Chemical Industry Co., Ltd.) in 150ml of tetrahydrofuran is prepared, and a solution including 14.5 g ofsodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.)in 60 ml of water is added thereto. The resulting mixture is stirred at60° C. for 6 hours under a nitrogen stream.

After allowed to cool, the mixture is poured into 500 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thendissolved in toluene. Impurities are removed from the solution by columnchromatography (silica gel), and recrystallization from atoluene/methanol mixed solvent is preformed, so that 3.3 g of2,6-bis(2′-thienyl)pyrazine is obtained (50% of the theoretical yield).

A solution including 3.0 g (12 mmol) of the resulting2,6-bis(2′-thienyl)pyrazine in 80 ml of N,N-dimethylformamide isprepared, and 5.5 g (31 mmol) of N-bromosuccinimide (hereinafter alsoreferred to as NBS, manufactured by Wako Pure Chemical Industries, Ltd.)is added thereto. The resulting mixture is stirred at 80° C. for 5 hoursunder a nitrogen stream.

After allowed to cool, the mixture is poured into 500 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thenrecrystallized from a toluene/methanol mixed solvent, so that 2.45 g of2,6-bis(5′-bromo-2′-thienyl)pyrazine is obtained (49% of the theoreticalyield).

A solution including 0.52 g (1.3 mmol) of the resulting2,6-bis(5′-bromo-2′-thienyl)pyrazine, 0.51 g (2.9 mmol) g of4-n-butylbenzeneboronic acid (manufactured by Wako Pure ChemicalIndustries, Ltd.), and 0.017 g (0.015 mmol) oftetrakis(triphenylphosphine)palladium(0) (manufactured by Tokyo ChemicalIndustry Co., Ltd.) in 25 ml of N-methylpyrrolidone is prepared, and asolution including 0.80 g (6.8 mmol) of sodium carbonate (manufacturedby Wako Pure Chemical Industries, Ltd.) in 5 ml of water is addedthereto. The resulting mixture is stirred at 80° C. for 6 hours.

After allowed to cool, the mixture is poured into 400 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thendissolved in toluene. The dissolved precipitate is purified by columnchromatography (silica gel) and recrystallized from a toluene/methanolmixed solvent, so that 0.45 g of compound (II-6) is obtained (69% of thetheoretical yield).

The resulting compound (II-6) has a melting point of 152° C. to 152.5°C.

The infrared absorption spectrum and ¹H-NMR spectrum of the resultingcompound (II-6) are shown in FIGS. 1 and 2, respectively.

Example 2 Synthesis of Compound (II-11)

A solution including 3.8 g (9.4 mmol) of2,6-bis(5′-bromo-2′-thienyl)pyrazine obtained using the process ofExample 1, 2.7 g (21 mmol) of 2-thiopheneboronic acid (manufactured byTokyo Chemical Industry Co., Ltd.), and 0.18 g (0.16 mmol) oftetrakis(triphenylphosphine)palladium(0) (manufactured by Tokyo ChemicalIndustry Co., Ltd.) in 200 ml of N,N-dimethylformamide is prepared, anda solution including 5.7 g (48 mmol) of sodium carbonate (manufacturedby Wako Pure Chemical Industries, Ltd.) in 30 ml of water is addedthereto. The resulting mixture is stirred at 90° C. to 100° C. for 4hours,

After allowed to cool, the mixture is poured into 700 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thendissolved in toluene. The dissolved precipitate is purified by columnchromatography (silica gel) and recrystallized from a toluene/methanolmixed solvent, so that 1.8 g of 2,6-bis(2′,2″-bithiophene-5′-yl)pyrazineis obtained (47% of the theoretical yield).

A solution including 1.36 g (12 mmol) of the resulting2,6-bis(2′,2″-bithiophene-5′-yl)pyrazine in 80 ml ofN,N-dimethylformamide is prepared, and 1.33 g (31 mmol) ofN-bromosuccinimide (manufactured by Wako Pure Chemical Industries, Ltd.)is added thereto. The resulting mixture is stirred at 70° C. for 5 hoursunder a nitrogen stream. After allowed to cool, the mixture is pouredinto 500 ml of water, and the resulting precipitate is separated byfiltration and washed with water. The precipitate is dried under reducedpressure and then recrystallized from a toluene/methanol mixed solvent,so that 1.43 g of 2,6-bis(5″-bromo-2′,2″-bithiophene-5′-yl)pyrazine isobtained (76% of the theoretical yield).

A solution including 1.0 g (0.18 mmol) of the resulting2,6-bis(5″-bromo-2′,2″-bithiophene-5′-yl)pyrazine, 1.0 g (0.44 mmol) of4-n-octylbenzeneboronic acid (manufactured by Tokyo Chemical IndustryCo., Ltd.), and 0.076 g (0.066 mmol) oftetrakis(triphenylphosphine)palladium(0) in 200 ml ofN-methylpyrrolidone is prepared, and a solution including 1.4 g (1.2mmol) of sodium carbonate (manufactured by Wako Pure ChemicalIndustries, Ltd.) in 5 ml of water is added thereto. The resultingmixture is stirred at 100° C. for 6 hours in a nitrogen stream.

After allowed to cool, the mixture is poured into 800 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thendissolved in toluene. The dissolved precipitate is purified by columnchromatography (silica gel) and recrystallized from toluene, so that0.23 g of compound (II-11) is obtained (16% of the theoretical yield).

The resulting compound (II-11) has a melting point of 197.5° C. to 199°C.

The infrared absorption spectrum and ¹H-NMR spectrum of the resultingcompound (II-11) are shown in FIGS. 3 and 4, respectively.

Example 3 Synthesis of Compound (III-7)

A solution including 4.0 g (22 mmol) of2,4-dichloro-6-methoxy-1,3,5-triazine (manufactured by Sigma-AldrichCorporation), 6.2 g (48 mmol) of 2-thiopheneboronic acid (manufacturedby Tokyo Chemical Industry Co., Ltd.), and 0.10 g (0.09 mmol) oftetrakis(triphenylphosphine)palladium(0) in 160 ml of tetrahydrofuran isprepared, and a solution including 12.3 g of sodium carbonate(manufactured by Wako Pure Chemical Industries, Ltd.) in 50 ml of wateris added thereto. The resulting mixture is stirred at 60° C. for 6 hoursunder a nitrogen stream.

After allowed to cool, the mixture is poured into 800 ml of water, andthe oil-soluble component is extracted with ethyl acetate. After theextract is concentrated under reduced pressure, impurities are removedfrom the concentrate by column chromatography (silica gel). Theconcentrate is further recrystallized from a toluene/methanol mixedsolvent, so that 4.55 g of 2,4-bis(2′-thienyl)-6-methoxy-1,3,5-triazineis obtained (74% of the theoretical yield).

A solution including 4.0 g (9.6 mmol) of the resulting2,4-bis(2′-thienyl)-6-methoxy-1,3,5-triazine in 50 ml ofN,N-dimethylformamide is prepared, and 6.2 g (35 mmol) ofN-bromosuccinimide (manufactured by Wako Pure Chemical Industries, Ltd.)is added thereto. The resulting mixture is stirred at 80° C. for 5 hoursunder a nitrogen stream.

After allowed to cool, the mixture is poured into 800 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thenrecrystallized from a toluene/methanol mixed solvent, so that 2.45 g of2,4-bis(5′-bromo-2′-thienyl)-6-methoxy-1,3,5-triazine is obtained (49%of the theoretical yield).

A solution including 1.03 g (1.3 mmol) of the resulting2,4-bis(5′-bromo-2′-thienyl)-6-methoxy-1,3,5-triazine, 1.0 g of4-n-butylbenzeneboronic acid (manufactured by Wako Pure ChemicalIndustries, Ltd.), and 0.021 g (0.018 mmol) oftetrakis(triphenylphosphine)palladium(0) (manufactured by Tokyo ChemicalIndustry Co., Ltd.) in 60 ml of N-methylpyrrolidone is prepared, and asolution including 3.0 g (6.8 mmol) of sodium carbonate (manufactured byWako Pure Chemical Industries, Ltd.) in 15 ml of water is added thereto.The resulting mixture is stirred at 90° C. for 6 hours under a nitrogenstream.

After allowed to cool, the mixture is poured into 400 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thendissolved in toluene. The dissolved precipitate is purified by columnchromatography (silica gel) and recrystallized from a toluene/methanolmixed solvent, so that 0.80 g of compound (III-7) is obtained (62% ofthe theoretical yield).

The resulting compound (III-7) has a melting point of 140° C. to 141° C.

The infrared absorption spectrum and ¹H-NMR spectrum of the resultingcompound (III-7) are shown in FIGS. 5 and 6, respectively.

Example 4 Synthesis of Compound (III-11)

A solution including 1.1 g (2.6 mmol) of2,4-bis(5′-bromo-2′-thienyl)-6-methoxy-1,3,5-triazine obtained using theprocess of Example 3, 1.0 g (8.0 mmol) of 2-thiopheneboronic acid(manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.04 g (0.035mmol) of tetrakis(triphenylphosphine)palladium(0) (manufactured by TokyoChemical Industry Co., Ltd.) in 40 ml of N-methylpyrrolidone isprepared, and a solution including 3.0 g (6.8 mmol) of sodium carbonate(manufactured by Wako Pure Chemical Industries, Ltd.) in 15 ml of wateris added thereto. The resulting mixture is stirred at 80° C. for 4 hoursin a nitrogen stream.

After allowed to cool, the mixture is poured into 400 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thendissolved in toluene. The dissolved precipitate is purified by columnchromatography (silica gel) and recrystallized from a toluene/methanolmixed solvent, so that 0.78 g of2,4-bis(2′,2″-bithiophene-5′-yl)-6-methoxy-1,3,5-triazine is obtained(71% of the theoretical yield).

A solution including 0.76 g (1.8 mmol) of the resulting2,4-bis(2′,2″-bithiophene-5′-yl)-6-methoxy-1,3,5-triazine in 35 ml ofN,N-dimethylformamide is prepared, and 0.68 g (3.8 mmol) ofN-bromosuccinimide (manufactured by Wako Pure Chemical Industries, Ltd.)is added thereto. The resulting mixture is stirred at 70° C. for 3 hoursunder a nitrogen stream.

After allowed to cool, the mixture is poured into 400 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thenrecrystallized from a toluene/methanol mixed solvent, so that 0.71 g of2,4-bis(5″-bromo-2′,2″-bithiophene-5′-yl)-6-methoxy-1,3,5-triazine isobtained (68% of the theoretical yield).

A solution including 0.65 g (1.1 mmol) of the resulting2,4-bis(5″-bromo-2′,2″-bithiophene-5′-yl)-6-methoxy-1,3,5-triazine, 0.45g (2.5 mmol) of 4-n-butylbenzeneboronic acid (manufactured by Wako PureChemical Industries, Ltd.), and 0.014 g (0.012 mmol) oftetrakis(triphenylphosphine)palladium(0) (manufactured by Tokyo ChemicalIndustry Co., Ltd.) in 80 ml of N-methylpyrrolidone is prepared, and asolution including 0.61 g (5.2 mmol) of sodium carbonate (manufacturedby Wako Pure Chemical Industries, Ltd.) in 4 ml of water is addedthereto. The resulting mixture is stirred at 90° C. for 6 hours.

After allowed to cool, the mixture is poured into 500 ml of water, andthe resulting precipitate is separated by filtration and washed withwater. The precipitate is dried under reduced pressure and thendissolved in toluene. The dissolved precipitate is purified by columnchromatography (silica gel) and recrystallized from toluene, so that0.22 g of compound (III-11) is obtained (30% of the theoretical yield).

The resulting compound (III-11) has a melting point of 171° C. to 173°C.

The infrared absorption spectrum and ¹H-NMR spectrum of the resultingcompound (III-11) are shown in FIGS. 7 and 8, respectively.

TABLE 3 Charge Ionization Solubility Com- Mobility Potential Dichloro-Tol- Chloro- pound (cm²/Vs) (eV) ethane uene benzene Example 1 II-6 2.2× 10⁻⁶ 5.76 A A A Example 2 II-11 1.7 × 10⁻⁵ 5.40 A B A Example 3 III-75.6 × 10⁻⁷ 5.85 A A A Example 4 III-11 1.1 × 10⁻⁵ 5.52 A A A

The nitrogen-containing heterocyclic compounds of Examples 1 to 4 eachhave high charge transporting properties and high solubility in organicsolvents suitable for use in the preparation of electronic devices.Therefore, they are useful as materials for organic photoreceptors andorganic electronic devices such as organic electroluminescence devicesand organic transistors.

The foregoing description of the embodiments of the present inventionhas been provided for the purposes of illustration and description. Itis not intended to be exhaustive or to limit the invention to theprecise forms disclosed. Obviously, many modifications and variationswill be apparent to practitioners skilled in the art. The embodimentswere chosen and described in order to best explain the principles of theinvention and its practical applications, thereby enabling othersskilled in the art to understand the invention for various embodimentsand with the various modifications as are suited to the particular usecontemplated. It is intended that the scope of the invention be definedby the following claims and their equivalents.

1. A nitrogen-containing heterocyclic compound represented by Formula(II):

wherein R¹ represents a hydrogen atom, a substituted or unsubstitutedalkyl group having 1 to 20 carbon atoms, or a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms; and n representsan integer of from 1 to
 3. 2. The nitrogen-containing heterocycliccompound according to claim 1, wherein the alkyl group is anunsubstituted alkyl group.
 3. The nitrogen-containing heterocycliccompound according to claim 1, wherein R¹ is a straight-chain alkylgroup.
 4. The nitrogen-containing heterocyclic compound according toclaim 1, wherein the alkoxy group represented by R¹ is a straight-chainalkoxy group.
 5. The nitrogen-containing heterocyclic compound accordingto claim 1, wherein the alkoxy group represented by R¹ is anunsubstituted alkoxy group.
 6. The nitrogen-containing heterocycliccompound according to claim 1, wherein the substituent R¹ is in 3- or4-positions of the benzene ring, relative to the thiophene ring which isin 1-position.
 7. The nitrogen-containing heterocyclic compoundaccording to claim 1, wherein in Formula (II), R¹ is an alkyl grouphaving 1 to 12 carbon atoms.